Hot water tank flue baffle



Nov. 24,1953 .Q OR OW 2,660,198

HOT WATER TANK FLUE BAFFL'E Filed 001;. 10, 1951 INVENTOR. C/orence 1% Narrow s g Y 4 70 4 am v1 ATTORNEYS Patented Nov. 24, 1953 HOT WATER TANK FLUE BAFFLE Clarence H. Morrow, Shaker Heights, Ohio, as-

signor to The Hotstream Heater Company, Cleveland, Ohio, a corporation of Ohio Application October 10, 1951, Serial No. 250,695

7 Claims. (01. 138-38) This invention relates to improvements in flue bafiies and more particularly to a flue baflle readily removable from or insertable into its enclosing flue.

One of the objects of the present invention is to provide a relatively rigid flue baflle especially designed for maximum heat removal from the hot flue gases.

Another object of the present invention is to provide in a flue baflle of the type set forth above a bendable portion intermediate its ends so that the baffle may be easily removed from or inserted into its enclosing flue within a very limited space.

, Other features of this invention reside in the arrangement and design of the arts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings, Fig. 1 is a perspective view of the-blank from which the finished baiile is formed;

Fig. 2 is a perspective view of the bafile in an intermediate stage in its manufacture;

Fig. 3 is a perspective view of the finished baffle;

Fig. 4 is a' vertical longitudinal sectional view of the dies in closed position forming the baffle shape; 7

Fig. 5 is a vertical transverse sectional view taken along the line 5- 5 of Fig. 4;

Fig. 6 is a vertical transverse sectional view taken along the line 66 of Fig. 4;

Fig. 7 is a vertical sectional view of a hot water tank and flue containing the baflle of this invention; while Fig. 8 is a vertical sectional view similar to Fig. 7 but showing the baffle being removed from the hot water tank flue within a small overhead clearance.

Before the flue baffie here illustrated is specifically described, it is to be understood that the invention here involved is not limited to the structural details or arrangement of parts here shown since bafiles embodying the present invention may take various forms. It also is to be understood that the phraseology or terminology herein employed is for purposes of description and not of limitation since the scope of the present invention is denoted by the appended claims.

While the bafile of this invention might be adapted for other uses, I have chosen to show the same used in a flue of a hot water tank. The flue baflie of this invention is especially designed for center-flue hot water tanks wherein the baflle forces the vertically rising, hot flue gases to impinge against and come in contact with the flue wall to give up their heat to the flue wall and the surrounding water in the hot water tank. The fi-ue baffle is especially designed to extract as much heat as possible from the hot flue gases. The bafile design also includes a weakened portion so that the bafile may be readily removed from the flue for cleaning purposes or for any other purpose desired.

The novel baflle is manufactured from an elongated stripof ductile material, shown at ill in Fig. 1. This strip or blank made of ductile material, for example, steel, is of uniform width and thickness throughout its length.

The first step in the manufacture of the balile is to stamp the blank shown in Fig. 1 into the baffle shape ll illustrated in Fig. 2. A set of dies consisting of upper die l2 and lower die l3, as shown in Figs. 4 to 6, perform this function. The dies I2 and I3 respectively have cavities I2a and [3d adapted to align when the dies are brought together and to form a cavity of rectangular parallelopiped shape. The upper die has inserted die pieces [2b and [2c in the cavity In adapted to align with the corresponding die pieces 13b and inserted in the lower die cavity I3a. These die pieces are preferably welded in place in their respective cavities and each has an inclined, thin, substantially straight line, metal bending edge. These metal blank engaging and bending edges are shown at 12b, [31), I20, and Be. The metal bending edges are alternately inclined in opposite directions, as clearly shown in Figs. 5 and 6. Every other set of metal bending edges, for example, metal engaging or bending edges lib and l3b', are inclined in the same direction. The metal bending edges of each set, edges lib and I312 or I20 and I30, are parallel to each other and spaced apart the thickness of the strip ill when the dies .12 and [3 are in their stamping or fully engaged position shown in Figs. 4 to 6. Grip members I2d and I30 on dies I2 and I3 respectively grip the ends of the strip I during the stamping operation and keep the ends in their original flattened condition. At approximately the longitudinal center of the cavities, I2a and I3a, another set of inserted die pieces are mounted similar to those previously described except this set has flat edges octagonal shaped in outline for engaging the upper and lower surfaces of the metal blank. The previously described inserted die .pieces had thin, substantially straight line edges.

The baflie shape II in Fig. 2 is the finished stamping coming from dies I2 and I3. The straight ends IIa, Ila have the same shape as the ends of the original blank or strip I0 since they were held by the grip members I2d, I311. Transverse bend lines III) are alternately inclined in opposite directions and were formed by the inclined, substantially straight line,'1netal blank engaging edges I21), I31), I and I, The portion of the baffleshape between each adjacent pair of bend lines IIb forms a smooth connecting curve. v The octagonal shaped, flat, ni'etalblank engagingedges at the center of the idieen'gage opposite sides of the metal blank and form a roughly octagonal shaped, flattened zone iIIc approximately l at the middle of the baffle shape 'II in Fig. 2. This flattened zone is a plane extending transversely and longitudinally of th'ebafile shape II. A line in this zone and extending across the widest dimension of the bafile and bisecting the opposite lateral sides of the octagon is transverse to the longitudinal axis of the same. This line in the flattened zone and the bend lines lIb are substantially equally spaced along the length of the ba'file shape I I.

The elongated bafile shape I I is relatively rigid and resists bending. It is of sinuous shape and has its opposite longitudinal edges alternately bent downwardly and upwardly to provide high and low points on an undulated curve wherein the low points on one side are opposite the high points on the other. The waves-or scallops have relatively sharp peaks and valleys. None of the longitudinally extending elements of the strip is a strai'g'ht line; each forms an undulated or Wavy curve. The high and low points on the longi- ,tudinal edges arearranged so that a line drawn through the high pointsonone edge and a line .drawn through the low points on the same edge taken with corresponding lines drawn through the corresponding points on the other edge-form the tour, longitudinal, straight line edges of a rectangular cylinder. This relationship exists sinceblank I13 is of uniform width and cavities 13a and 131; forma rectangular -paralle1opiped while the metal blank engaging edges I21), I31), fie 'andfISc' form substantially the same angle th' h' r at e w the second step of thefbafiie manufacture, 'T=s'h'apedslots IId are punched in theopposite transverse ends 'o'f the octagonal shaped flattened zone I I0. "Each of the T-shapedslots has a transverse slot H d cu't'inirom theopposite longitudinal edges 'or sides of the bafiieshape "II and forming the stem of the T. These transverse slots -I Id are in alignment witheach other. The top cross bars IId" of the T's are parallel to the longitudinal edge'sof the bafileshape I I and to each other. These T'-shaped slot form a weakened zone Me of reduced width between the cross bars Nd. and the flattened zone IIc form a bendable por- These T-shaped slots I I'll 4 tion intermediate the ends of the relatively rigid baille.

A suspension or supporting means may be provided on one end of baiile shape II, if desired. One type of such means is shown in the drawings as a supporting or suspension bar l5 welded to one end of and transversely extending with respect to baille shape I I.

The center-flue hot water tank It in Fig. '7 has the completed baffle. The water jacket I! surrounds thevertical, elongated, central, cylindric'al flue I8 in the hot water tank. The com plted baflle, consisting of the bafl'l'e shape II, T- slots I Id and the suspension bar I5, is suspended in the flue I8 with the outer edges of the bar I5 engaging on'the top of the cylindrical wall of the and removable from the bore of the cylindrical flue with the longitudinal edges of the baffle being "in-close proximity to the flue bore surfaces. Very little flue gas can pas directly up the bore surface of the flue without being deflected'by the bafile in view of this close flt. The shape "of the bafile controls the upward travel of substantially all of the flue gas traveling through the flue I8. Since every longitudinally extending element of the flue bafile has a sinuous or'wavy shape, none of the gas can pass directly up the flue but instead is deflected from one portion of the flue wall to another so that a maximum amount of heat is extracted from the hot gases to heat the water.

Sometimes the baffle must be withdrawn from the flue for cleaning or replacement or for some other reason within a very limited overhead space, as shown in Fig. 8. Since the baflle shape I I is very rigid and resists bending, it cannot be readily bent to withdraw it from the flue, and since the baflle shape II has been especially designed for maximum heat extraction from the hot flue gases, it is not desirable to materially change its design which would alter its efiicient gas flow and heat exchange characteristics. The bendable portion or weakened portion at the center of the baiiie presents an ideal solution. It is inexpensive to manufacture the T-shaped slots "I'I'd "and the flattened zone He in the stamping operations. "No expensive hinge must be added to the 'bafile so that the parts may be bent with respect to each other during removal of the baffle. The weakened portion interferes very little with the gas flow pattern-for high 'he'at'transfer inherent in the well-designed baflle shape II.

The "ba'ffie may be'very readily withdrawn from the top of the flue I8 within-'a-limited overhead space, for'exarr'iple18incl-res, as seen in 8. Frequently, the =ceilirig -or overhead interfering member 19 prevents the withdrawal of the bafile from'the flue without bendingof the-baiile. Baffle shape II is readily bent along a transverse line through the weakened portion l-I'e to reduce the distance between the ends' of the b'a'file so thatit 'may'bereadily removed from the top of the flue within a space above the flue substantially less than the length of the -b'a'flle. No part of the bafile protrudes above a plane -located substantially less than the length of the baffle above the top of the flue.

'After the baiile-has'been'removed and-cleaned or. otherwise treatedor-examined, it-may bere'ad- 'ily reinserted within-the'flue I8 by a procedure in reverse of the removal procedure, set forth above. Of course, a replacement baflle may be inserted, -if desiredinstead of reinserting the original baflle. The reinserted or replacement baflle will then assume the position shown in Fig. 7. It should be noted that this bending never distorts the well designedgas flow, rigid surface of the major portion of the baflie. Only the weakenedzone or neck H2 is bent or distorted. This bendable area He will stand numerous bends without rupture or fracture and the rigid major portions of the baflie on each side of the bendable area lle will return substantially to their original position after the baiiie is inserted into flue Hi.

This invention contemplates, of course, that several weakened or bendable portions could be provided along the length of the baffle to divide it into thirds or quarters, if desired, so that the baffle could be removed from the top of the flue within a smaller overhead clearance than onehalf of the length of the battle, which latter clearance is shown in Fig. 8.

It should now be apparent that this application discloses a new and novel baffle design wherein the baffle controls the flow of substantially all the flue gas and prevents excessive leakage past its edges, extracts the maximum amount of heat from the hot flue gases, is rigid throughout most of its length so as to readily retain its shape in use, and has a bendable portion intermediate its ends which does not interfere with normal gas flow but permits the baffle to be withdrawn from or inserted into the top of the flue within a very small overhead space.

Various changes in details and arrangement of part can be made by one skilled in the art without departing from the spirit of this invention or the scope of the appended claims.

What I claim is:

1. A baffle comprising a strip having opposite ends and having over substantially its whole length, its longitudinal edges alternately bent downwardly and upwardly to provide high and low points, the low point on one side being opposite the high point on the other, whereby said baflie is rigid and resists bending, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite ends.

2. A bafiie comprising a strip having opposite ends and having over substantially its whole length its longitudinal edges alternately bent downwardly and upwardly to provide high and low points, the low point on one side being opposite the high point on the other, the high and low points being arranged so that a line drawn through the high points on one edge and a line drawn through the low points on the same edge and corresponding lines drawn through the corresponding points on the other edge are straight lines forming in transverse cross section the four corners of a rectangle, whereby said baflle is rigid and resists bending, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite ends.

3. A baffle comprising a strip of uniform width having opposite ends and having over substantially its whole length its longitudinal edges alternately bent downwardly and upwardly to provide high and low points, the low point on one side being opposite the high point on the other, the high and low points being arranged so that a line drawn through the high points on one edge and a line drawn through the low points on the same edge and corresponding lines drawn through the corresponding points on the other edge are straight lines forming in transverse cross section the four corners of a rectangle, whereby said baflie is rigid and resists bending and said bafiie is readily insertable into the bore of a cylindrical flue with the longitudinal edges of said baiiie being in close proximity to the flue bore surface when the diameter of the bore is substantially equal to but slightly greater than the width of said strip, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite ends.

4. A baffle comprising a strip having opposite ends and having over substantially its whole length its longitudinal edges alternately bent downwardly and upwardly to provide high and low points, the low point on one side being opposite the high point on the other, whereby said baffle is rigid and resists bending, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite ends, said bendable portion comprising a flattened zone extending transversely on said strip and having transverse slots cut in from opposite sides of said strip.

5. A bafiie comp-rising a strip of uniform Width having opposite ends and having over substantially its whole length its longitudinal edges alternately bent downwardly and upwardly to provide high and low points, the low point on one side being opposite the high point on the other, the high and low points being arranged so that a line drawn through the high points on one edge and a line drawn through the low points on the same edge and corresponding lines drawn through the corresponding points on the other edge are straight lines forming in transverse cross section the four corners of a rectangle, whereby said baflle is rigid and resists bending and said baiile is readily insertable into the bore of a cylindrical flue with the longitudinal edges of said bafiie being in close proximity to the flue bore surface when the diameter of the bore is substantially equal to but slightly greater than the width of said strip, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite ends, said bendable portion comprising a flattened zone extending transversely on said strip and having transverse slots cut in from opposite sides of said strip.

6. A bafiie comprising a strip having opposite ends and having longitudinally spaced bend lines over substantially its whole length and extending across the full strip width with said bend lines being alternately inclined in opposite directions so that the longitudinal edges of the strip are alternately bent downwardly and upwardly to provide high and low points, the low points on one side being opposite the high points on the other, the portion of said strip between each pair of bend lines forming a smooth curve connecting said bend lines whereby said baffle is rigid and resists bending, and a bendable portion intermediate the ends of said strip whereby said strip may be bent to reduce the distance between said opposite edges.

7. A baflle comprising a strip having opposite ends and having longitudinally spaced bend lines over substantially its whole length and extending across the full strip width with said bend lines being alternately inclined in opposite directions so that the longitudinal edges of the strip are alternately bent downwardly and upwardly to 

